Scheer just wrapped a two-day visit to Washington, D.C., where he met with Republican Senator Lisa Murkoski, U.S. Chamber of Commerce vice-president Neil Herrington, and Republican Congressman Chris Smith among others.

“I’ve learned the threat is real,” Scheer told Global News in an interview from Washington.

That ‘threat’ – that U.S. President Trump could withdraw from NAFTA – isn’t just posturing, according to Scheer.

“This is not something that should be taken lightly,” he said. “I would certainly encourage the Liberal government to really pour it on, really increase their efforts, to find new avenues to get in front of decision-makers down here in Washington.”

WATCH BELOW: If U.S. withdraws from NAFTA lots of uncertainties: Freeland

Scheer says there were some encouraging signs during his visit that a full-court press could work.

“Sometimes it’s hard for Canadians to see a U.S. president doing things that we firmly believe would hurt the U.S. economy just as much as it would hurt ours, and you sometimes wonder why someone would do something that’s against their own self interest,” he said.

“The good news is when it comes to some of the protectionist measures that the Trump administration is trying to insert, there doesn’t seem to be a lot of grass root support for that throughout the U.S.”

During his trip, Scheer made a point of saying he would not be critical of the Liberals while south of the border, and instead present a united front on NAFTA.

He hasn’t adhered to the same edict on other trade issues in the past — last month, Scheer tweeted that he expressed his disappointment in the prime minister to the Japanese ambassador to Canada. The tweet came after it was reported Trudeau didn’t show up for a significant Trans Pacific Partnership (TPP) meeting with his counterparts.

Scheer also threw shade on Trudeau’s trade record in a year-end interview with The West Block in December.

“I’ve come to the conclusion that he isn’t actually in favour of free trade,” Scheer said at the time. “Everything Justin Trudeau touches turns into a disaster.”

The Conservative leader’s Washington visit concluded with very different rhetoric.

“We’ve been here to support the government’s efforts, to show that united front and I believe we’ve been very successful.”